How to remove the blogger navigational bar

Open the template code (Dashboard > Layout > Edit HTML and paste the following code on the template:

#navbar-iframe {
height:0px;
visibility:hidden;
display:none;
}

example

...
<b:skin><![CDATA[/*
-----------------------------------------------
Blogger Template Style
 Name:     Rounders
Designer: IT Assist
URL:      www.itassist-vanuatu.blogspot.com
Date:     13 Sept 2011
----------------------------------------------- */

#navbar-iframe {
   display: none !important;
}

/* Variable definitions
  ====================
   <Variable name="mainBgColor" description="Main Background Color"
              type="color" default="#fff" value="#ffffff">
   <Variable name="mainTextColor" description="Text Color" type="color"
             default="#333" value="#333333">
    ...